Explanation:

Let’s break it down, step by step:

- Look at the pattern. For each pair, the letters are reversed, and the number changes.

- First pair: ABC2 ? ZYX7

- ABC reversed is CBA, but here it’s ZYX. What's happening? They’re using the letters from the back of the alphabet: reverse order, but also starting from the end, matching positions.

- 2 changes to 7: difference is +5.

- Second pair: PQR21 ? KJI26

- PQR reversed and shifted: matches K, J, I (again, reverse order from P backwards).

- 21 + 5 = 26.

- Third pair: MNO11 : ?

Let’s keep the pattern:

- MNO (13, 14, 15 in alphabet) – reversed and shifted like before.

- Highest possibility is NML (N = 14, M = 13, L = 12), following the reverse trend.

- Add 5 to 11 ? 16.

Now the options:

1. NML16 (matches our pattern: reverse order, add 5)

2. KLM14 (wrong order, and 14 isn’t +5)

3. NLM14 (order’s off, number’s wrong)

4. MKL16 (order’s off)

So, option 1 is the match.